Edge fusion back projection GAN for large scale face super resolution

Face super-resolution is an important low-level vision task that has wide applications. Existing deep-learning-based face super-resolution (SR) methods often optimize the image super-resolution network by directly minimizing the pixel or feature level distance between the synthetic low-resolution face and the ground truth face image. These methods usually generate blur or over smooth results and lack of high-frequency face details. These are especially true for making high super-resolution of faces. Say for example, a super-resolution of 16x, only 0.4% of the reference data points are available. To address the problem, we propose a novel network with edge fusion, back projection, and GAN prior (EFBPGAN) which can significantly improve the visual quality and generate realistic faces. To further make use of the spatial information and keep the structural consistency, we have developed new edge fusion and spatial fusion modules. We also propose a back projection extensive based coarse to fine SR pipeline to suppress the distortion and artifacts caused by GAN. Much experimental work has been done, results of which show that our proposed EFBPGAN can outperform the state-of-the-art approaches not only on numerical metrics but also on subjective visual evaluations.